How to use this default interest calculator
This tool estimates the default interest (temerrüt faizi, often called mora interest) that has built up on an unpaid Turkish debt between the day the debtor fell into default and the day you run the calculation. Fill in four fields and it returns the annual rate applied, the interest accrued and the total recoverable figure, with a summary you can print or copy straight into a letter of demand.
- Principal and currency. Enter the unpaid amount and the currency the debt is owed in. For a foreign-currency invoice, keep it in that currency — the rate basis for hard-currency debts is different, and converting to lira first distorts the result.
- Default date. This is the day the debtor was placed in default — not the day you issued the invoice. Where the contract fixes a calendar due date the two can coincide; otherwise default normally starts with a formal notice or the service of an enforcement payment order. See “Starting the clock” below before you choose the date.
- Calculation date. Leave it at today to see the position now, or set it to a future hearing or settlement date to see where the claim lands.
- Rate basis. Pick the line that matches your debt:
- Foreign currency statutory rate — Law No. 3095 art. 4/a: where no higher contractual or default rate was agreed, interest on a foreign-currency debt runs at the highest rate paid by state banks on a one-year deposit in that currency. You enter this rate. It is not a single published official figure — it depends on what the state banks were paying on that currency — so the tool carries no number for it and asks you instead.
- Commercial default / advance rate — Law No. 3095 art. 2: in commercial affairs the creditor may claim interest at the Central Bank’s short-term advance rate applied on 31 December of the previous year where that rate is higher than the statutory rate, even with no agreement between the parties. For 2026 that rate is 39.75%.
- General statutory interest — Law No. 3095 art. 1: the baseline rate where the parties fixed nothing. Since the amendment in force on 31 July 2026 it is set at 80% of the Central Bank’s short-term credit rediscount rate applied on 31 December of the previous year, with a mid-year revision if the rate on 30 June differs by five points or more. On that basis the rate is 31.00%.
- Unpaid supply invoice between businesses — TTK No. 6102 art. 1530/7: where goods or services were supplied between commercial undertakings and the contract fixes no default rate, the rate is the one the Central Bank announces each January. For 2026 it is 43.00%. If your claim is an unpaid invoice for goods or services, start here rather than with the art. 2 advance rate.
- Agreed contractual rate — use the rate in your contract; you enter it. Art. 2 adds a floor worth knowing: where no default rate was agreed but the contractual interest rate is higher than the statutory figures, default interest cannot be less than the contractual rate.
Where these figures come from
Each lira rate in this calculator is read off an official text, and the result panel prints the source beside the rate it used. These are the figures held, the periods they cover and the texts they come from.
| Basis | Period | Rate | Official source |
|---|---|---|---|
| General statutory interest kanuni faiz — Law 3095 art. 1 |
From 31 July 2026 | 31.00% | Law No. 3095 art. 1 as amended by Law No. 7589 art. 10, in force 31 July 2026: 80% of the Central Bank’s short-term credit rediscount rate applied on 31 December of the previous year. That rate was fixed at 38.75% by the Central Bank communiqué published in the Official Gazette of 20 December 2025, no. 33113, and was unchanged on 30 June 2026, so the five-point mid-year revision was not triggered. 80% of 38.75% is 31.00%. |
| General statutory interest Law 3095 art. 1, former wording |
1 June 2024 – 30 July 2026 | 24.00% | Presidential Decision no. 8485, Official Gazette of 21 May 2024, setting the art. 1 rate at an annual 24% with effect from 1 June 2024. Until the July 2026 amendment, art. 1 fixed a rate in the law itself and allowed the executive to vary it. |
| Commercial default rate avans faizi — Law 3095 art. 2 |
2026 | 39.75% | Art. 2 lets a creditor in commercial affairs claim the Central Bank’s short-term advance rate applied on 31 December of the previous year where it is higher than the art. 1 rate. The same communiqué of 20 December 2025 (Official Gazette no. 33113) set that advance rate at 39.75%; it was unchanged on 30 June 2026, so no mid-year revision was triggered. 39.75% is higher than the art. 1 rate of 31.00%, so in commercial affairs it can be claimed with no agreement between the parties. |
| Commercial default rate Law 3095 art. 2 |
1 July – 31 December 2025 | 44.25% | Art. 2 provides that where the advance rate on 30 June differs from the rate applied on 31 December of the previous year by five points or more, the 30 June rate governs the second half of the year. The rate in force on 30 June 2025 was 44.25% (Central Bank communiqué, Official Gazette of 8 March 2025, no. 32835), exactly five points below the 49.25% applied on 31 December 2024 — which meets the statutory test. |
| Commercial default rate Law 3095 art. 2 |
1 January – 30 June 2025 | 49.25% | Central Bank communiqué published in the Official Gazette of 28 December 2024, no. 32766, setting the short-term advance rate at 49.25%. That was the rate applied on 31 December 2024, which art. 2 takes as the figure for the following year. |
| Supply of goods or services TTK 6102 art. 1530/7 |
2026 | 43.00% | Central Bank communiqué published in the Official Gazette of 2 January 2026, no. 33125, setting the art. 1530/7 late-payment rate at an annual 43.00% with effect from 1 January 2026, together with a minimum collection-cost compensation of 2,020.00 TRY. For 2025 the corresponding figures were 53.25% and 1,475.00 TRY (Official Gazette of 2 January 2025, no. 32770). |
| Foreign-currency debts Law 3095 art. 4/a |
— | you enter it | Art. 4/a applies the highest rate paid by state banks on a one-year deposit in the currency of the debt, absent a higher agreed rate. There is no single official published figure for this, so the tool holds no number for it and asks you for the rate your bank evidence shows. |
Two points on the earlier history, because an old debt may straddle them. The fixed-rate system began with Law No. 5335 art. 14 (Official Gazette of 27 April 2005), which set the art. 1 rate at an annual 12%, and that figure was reduced to 9% with effect from 1 January 2006 by a Council of Ministers decision published in the Official Gazette of 30 December 2005. This calculator holds art. 1 rates back to 1 June 2024, and commercial advance and art. 1530/7 supply rates back to 1 January 2025: if your period starts earlier, it prices only the days it can source and tells you how many days it left out, rather than applying a figure it cannot stand behind. The rate in force on those earlier dates has to be confirmed and that part of the claim added separately.
The figures above were last checked against the official texts on 6 October 2026, and are rechecked every January and July — the dates on which the Central Bank rates that art. 1 and art. 2 refer to can change.
What to do with the number. The figure belongs in the payment demand and then in the enforcement request, because interest continues to run until payment. If you are at the beginning, start with how commercial debt recovery works in Türkiye; if the debtor has already objected to an enforcement proceeding, see the annulment of objection lawsuit; if you are worried the money will move, see freezing a debtor’s bank accounts; and if the debt is already covered by a judgment obtained abroad, see enforcing a foreign judgment or award.
How interest on unpaid debts works in Turkish law
In cross-border business with Türkiye, an unpaid invoice or contractual default does not remain static. Under Turkish law, statutory interest accrues automatically once the debtor is placed in formal default (mütemerrit). The legal framework governing interest is set out in Law No. 3095 on Legal Interest and Default Interest, the Turkish Code of Obligations (TBK No. 6098), and the Turkish Commercial Code (TTK No. 6102).
Statutory Legal Interest vs. Commercial Advance Interest
Turkish law draws a fundamental distinction based on the nature of the parties and the underlying transaction:
- Statutory Legal Interest (Kanuni Faiz): Governed by Article 1 of Law No. 3095, this is the baseline statutory rate for civil claims, tort damages, and non-commercial contracts.
- Commercial Advance Rate (Avans / Ticari Temerrüt Faizi): Governed by the second paragraph of Article 2 of Law No. 3095. Where the debt arises from a commercial affair, the creditor may claim interest at the Central Bank’s short-term advance rate applied on 31 December of the previous year, if that rate is higher than the art. 1 rate — and may do so even with no agreement between the parties.
- Late payment for supply of goods or services (TTK Article 1530): A separate and higher regime, and the one that usually fits an unpaid B2B invoice. Where goods or services are supplied between commercial undertakings, art. 1530 puts the debtor in default without any notice at the contractual due date, or at the end of the statutory thirty-day period where no due date was agreed, and entitles the creditor to interest even if none was stipulated. Under paragraph 7, where the contract fixes no default rate or the rate clause is invalid, the Central Bank announces the applicable rate every January — a figure which the paragraph requires to be at least 8% above the commercial default rate under Law No. 3095. The same announcement sets a minimum sum claimable for the costs of collecting the debt: 2,020.00 TRY for 2026 and 1,475.00 TRY for 2025. That sum is a separate head of claim and is not included in the interest figures this tool produces.
These two are easy to confuse, and the difference is money: for 2026 the art. 2 advance rate is 39.75% while the art. 1530/7 supply rate is 43.00%. Which one applies turns on whether your claim is for the price of goods or services supplied between commercial undertakings, and on what the contract says about interest.
Foreign Currency Debts in Türkiye (USD, EUR, GBP)
Under Article 4/a of Law No. 3095, where a monetary debt is denominated in a foreign currency (such as USD, EUR, or GBP), the creditor is entitled to demand default interest calculated at the highest interest rate paid by Turkish state banks on one-year foreign currency deposits for that specific currency.
This rule protects international suppliers and creditors against Turkish Lira inflation while ensuring that unpaid hard-currency receivables accumulate realistic commercial yields throughout the recovery process.
Starting the Clock: Notice of Default (İhtarname) vs. Payment Orders
Under Turkish Code of Obligations Article 117, interest does not begin running simply because an invoice was sent, unless a specific calendar due date was established by contract. To trigger statutory default interest, the creditor must usually serve a formal notarial notice of default (ihtarname) or initiate formal enforcement proceedings (icra takibi) through the Turkish execution offices.
Precautionary Attachment (İhtiyati Haciz): Freezing Assets Early
The biggest risk in commercial recovery is not proving the debt, but having the debtor empty its bank accounts or transfer real estate while litigation is pending. Under Execution and Bankruptcy Law (İİK) Article 257, foreign creditors can apply to Turkish commercial courts for a precautionary attachment order (ihtiyati haciz) to freeze the debtor's Turkish bank accounts, trade receivables, vehicles and real estate before the debtor receives formal notice.
Scope. This page is general information about Turkish law and procedure. It is not legal advice, it is not an assessment of your situation, and reading it does not create a lawyer-client relationship. Statutory figures, thresholds and rates are revised periodically — check the current position before relying on any of them. Any particular case turns on its own documents and facts.